Remove the air duct cover.
Disconnect the PTC lead connector from the cable.
Connect the PTC heater to a rated power source on the rating label. If the PTC heater
fails to operate, it is defective and must be replaced.
8.4.7 OVERLOAD PROTECTOR
The overload protector prevents the compressor from burning out its electrical windings in the
event the compressor becomes overheated or draws too much current. The overload trips,
opening the circuit to the compressor. If it does this repeatedly, the compressor is said to be
cycling on the overload. Cycling on the overload may be caused by:
1. Insufficient air circulation around the compressor and condenser.
2. Pull-down on the compressor, caused by a large quantity of warm food placed in the
refrigerator.
3. Compressor stalling due to lack of pressure unloading.
4. Low line voltage.
5. Defective start relay.
6. Defective winding in the compressor or shorted windings.
Testing the Overload Protector
Disconnect the unit from the power source.
To test the overload protector, remove the compressor terminal cover. Examine the bottom of
the overload for signs of arcing. If signs of arcing are present, either check for continuity or
connect a jumper wire across the terminals. If using a jumper wire, plug in the line cord and set
the temperature control to a cold setting. If the compressor starts, the overload is defective and
must be replaced. If the compressor fails to start, check for a defective start relay or
compressor.
1. Remove the PTC and overload from the compressor.
2. Connect one ohmmeter probe to the compressor shell. Make sure the probe makes good
contact with bare metal. One at a time, connect the other ohm-meter probe to each of the
three compressor terminals.
3. If the meter shows no continuity to ground, install PTC and overload protector to the
compressor's terminals. If the meter indicates the compressor terminals are grounded,
replace the compressor.
4. Attach a jumper wire across the overload terminals.
5. Make sure the jumper wire does not short to ground.
6. Reconnect the unit to power source. If the compressor starts, the overload protector is
defective and must be re-placed.
8.4.8 PTC STARTING DEVICE
The PTC solid state starting device is a push-on component mounted to the start and run
terminals of the compressor. This device is connected in parallel with the run capacitor and is in
series with the compressor start windings. This will produce a short circuit across the run
capacitor during the compressor starting sequence and full current is applied to the start
windings as well as the main winding. Since the PTC device is temperature sensitive, a variance
in its temperature causes a change in its resistance. When current is first applied to the
